Experimental Investigation of the Mechanical Behaviors of Grouted Sand with UF-OA Grouts

Jin, Yuhao; Han, Lijun; Meng, Qinglin; Ma, Dawei; Han, Guansheng; Gao, Furong; Wang, Shuai

doi:10.3390/pr6040037

Cited by 9 publications

(7 citation statements)

References 26 publications

(24 reference statements)

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“…For evaluating the flow behavior through the rock fractures, using the Reynolds number (Re) (ratio of inertial forces to viscous forces) to quantify the onset of nonlinear flow: Re = ρQ/µw (6) In order to analyze nonlinear flow behavior through the fracture, T 0 and T were introduced in the research [37], in which the Forchheimer formula (Equation (3)) was rewritten:…”

Section: Normalized Transmissivitymentioning

confidence: 99%

“…These figures indicate that the grouts made of ultrafine cement can penetrate into smaller fractures more easily than the other two kinds of cement grouts, because the former contained substantial amounts of tiny cement grains. The ultrafine cement grouts have been widely used in the reinforcement for underground engineering in the past few decades due to its more stable physical and mechanical properties, greater range of strength adjustability, and better permeability, as well as non-polluting nature [48]. Therefore, the ultrafine cement grouts with W/C ratios of 0.8, 1.0, 1.2, 1.5, and 2.0 were selected in the experiment.…”

Section: Grout Materialsmentioning

confidence: 99%

“…Fractured rocks are widely distributed in underground engineering due to geological processes or excavation disturbance, which brings great safety hazard to engineering stability [1][2][3][4]. Grouting is an effective method for controlling groundwater inrush and improving the mechanical properties of fractured rocks in underground mining and engineering [5][6][7][8][9]. In order to acquire a better understanding of the grouting mechanism of fractured rock, many experimental studies have been performed in recent decades.…”

Section: Introductionmentioning

confidence: 99%

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Experimental Investigation of Grout Nonlinear Flow Behavior through Rough Fractures

Jin

Han

et al. 2019

Processes

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This research experimentally analyzed the impacts of various water cement (W/C) ratios of ultrafine cement grout material and normal loads FN applied to fractures on grout nonlinear flow behavior through a rough plexiglass fractured sample. An effective self-made apparatus was designed and manufactured to conduct the stress-dependent grout flow tests on the plexiglass sample containing rough fractures. At each W/C ratio, the grout pressure P increased from 0 to 0.9 MPa, and the normal loads FN ranged from 666.3 to 1467.8 N. The results of the experiments indicate that (1) the Forchheimer’s law can be used to express the results of grout nonlinear flow through rough fractures. Moreover, both nonlinear coefficient a and linear coefficient b in Forchheimer’s law decreased with the increase of the W/C ratio, but increased with the increase of the FN value. (2) For normalized transmissivity, with the increase of Re, the decline of the T/T0–Re curves means that the grout flow behavior through the fracture mainly went through three stages: the viscosity effect, then the weak inertia effect, and finally the strong inertia effect. The three stages showed that with the increase of Re, the grout flow state changed from linear to nonlinear. Moreover, with the increase of the W/C ratio, the Forchheimer coefficient β decreased. (3) At a given FN, the critical grout hydraulic gradient Jc decreased, but the critical Reynolds number Rec increased as the W/C ratio increased; at a given W/C ratio, Jc increased, but Rec decreased as FN increased.

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Section: Normalized Transmissivitymentioning

confidence: 99%

Section: Grout Materialsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Experimental Investigation of Grout Nonlinear Flow Behavior through Rough Fractures

Jin

Han

et al. 2019

Processes

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“…Related studies have found that the particle size of sand has a great effect on the strength of cemented similar materials [18,19]. Some studies consider that the increase of small sand particles can improve the mechanical properties of cementitious materials to a certain extent [20,21]. Jinxiao Jia believed that the smaller the particle size is, the fewer defects on the surface, so the mechanical strength increases with decreasing particle size [22]; On the contrary, Haifei Lin found that the larger the sand size is, the larger the contact area between the sand particles is.…”

Section: Introductionmentioning

confidence: 99%

Effect of Sand Particle Size on Microstructure and Mechanical Properties of Gypsum-Cemented Similar Materials

Guan

Zhang

et al. 2020

Materials

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To identify mechanism of sand particle size effect on the mechanical properties of gypsum cement, 11 grades of sand particles with a size of 0.1–3 mm were used to produce 99 specimens for uniaxial compression and permeability coefficient testing. Based on this, the distribution characteristics of internal stress and horizontal displacement are discussed using the numerical analysis. The results obtained show that the sand particle size effect on the uniaxial compressive strength of similar materials is negatively correlated within the range from −16.51% to 49.79%. SEM observations imply that, in the case of small particle sizes, gypsum crystals develop into denser needle-like structures, while for larger particle sizes, they are mostly loose lamellar structures. Permeability tests indicated that the larger the sand particle size, the greater the permeability, indicating that the internal pore connectivity is better, and the crevices are easier to penetrate when the specimen is compressed. Numerical simulations indicated that the larger the particle size, the larger the extreme deformation value of the specimen in the horizontal direction, and the more uneven the deformation distribution. In addition, specimens with larger particle sizes had a larger total area, where the tensile stress exceeded the ultimate tensile strength, and were more prone to tensile failure.

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“…Fractured rock masses (Figure 1(a)) are widely distributed in underground engineering due to geological action or excavation disturbance, which may bring serious safety hazard to the engineering stability [1][2][3][4]. Grouting is a useful way for controlling groundwater inrush and improving mechanical properties of fractured rocks in underground mining and engineering [5][6][7][8][9]. In order to acquire a better understanding of the grouting mechanism of fractured rock, lots of experimental studies have been performed in recent decades.…”

Section: Introductionmentioning

confidence: 99%

Cement Grout Nonlinear Flow Behavior through the Rough-Walled Fractures: An Experimental Study

Jin

Han

et al. 2020

Geofluids

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This research experimentally studied the effects of various fracture roughness (characterized by the fractal dimension D) and normal stress (normal loads FN) applied to fracture on ultrafine cement grout nonlinear flow behavior through rough-walled plexiglass fractured sample. A high-precision and effective sealing self-made apparatus was developed to perform the stress-dependent grout flow tests on the plexiglass sample containing rough-walled fracture (fracture apertures of arbitrary variation were created by high-strength springs and normal loads according to design requirements). The real-time data acquisition equipment and high-precision self-made electronic balance were developed to collect the real-time grouting pressure P and volumetric flow rate Q, respectively. At each D, the grouting pressure P ranged from 0 to 0.9 MPa, and the normal loads FN varied from 1124.3 to 1467.8 N. The experimental results show that (i) the Forchheimer equation was fitted very well to the results of grout nonlinear flow through rough-walled fractures. Besides, both nonlinear coefficient (a) and linear coefficient (b) in Forchheimer’s equation increased with increase of D and FN, and the larger the FN was, the larger the amplitude was. (ii) For normalized transmissivity, with the increase of Re, the decline of the T/T0−β curves mainly went through three stages: viscous regime, weak inertia regime, and finally strong inertia regime. For a certain D, as the normal load FN increased, the T/T0−β curves generally shifted downward, which shows good agreement with the single-phase flow test results conducted by Zimmerman. Moreover, with the increase of D, the Forchheimer coefficient β decreased. However, within smaller FN, β decreased gradually with increasing D and eventually approached constant values. (iii) At a given FN, Jc increased with increasing D.

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Experimental Investigation of the Mechanical Behaviors of Grouted Sand with UF-OA Grouts

Cited by 9 publications

References 26 publications

Experimental Investigation of Grout Nonlinear Flow Behavior through Rough Fractures

Experimental Investigation of Grout Nonlinear Flow Behavior through Rough Fractures

Effect of Sand Particle Size on Microstructure and Mechanical Properties of Gypsum-Cemented Similar Materials

Cement Grout Nonlinear Flow Behavior through the Rough-Walled Fractures: An Experimental Study

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